"After all the experiences that we have, even 30 years after the episode, we (Singapore) still are not in any way attempting to abolish the ISA," said Mr Cheng.

Mr Tsang said Singapore should learn from Asian countries such as South Korea and Taiwan, which have become "great powerhouses" both economically and in terms of democratic freedoms.

Historian Thum Ping Tjin, also spoke, urging the Government to release evidence for the Operation Spectrum arrests. He said: "Thirty years is a reasonable amount of time where we begin to get perspective on the past."

The Government had previously said it would not scrap the ISA as it remained "relevant and crucial" to keep the country safe and secure.